CO2 accumulation in bioreactor suspension cultures of Cyclamen persicum Mill. and its effect on cell growth and regeneration of somatic embryos

CO2 accumulation in different culture systems containing embryogenic cell suspension cultures of cyclamen (Cyclamen persicum Mill.) was analyzed. In bioreactors equipped with a bubble-free or a bubble aeration system, CO2 mole fractions in the gas phase of more than 10% were determined whereas in Erlenmeyer flasks, CO2 mole fractions were below 2%. CO2 accumulation in bioreactors was severely growth inhibiting in comparison to the flasks. By removing CO2 in the aeration gas of a bubble-free aerated bioreactor, cell growth comparable to that in flasks was achieved. The regeneration ability of cell suspensions after being cultured in bioreactors with CO2 accumulation was better than those after culture in bioreactors without CO2 accumulation or in flasks.